// 函数参数尾逗号
function clownsEverywhere(
    param1,
    param2
  ) { /* ... */ }
  
  clownsEverywhere(
    'foo',
    'bar'
  );
  function bar () {
      console.log('----')
  }
  console.log(bar.toString());
  let a = [];
  console.log(Object.prototype.toString.call(a))